### Electricity and Magnetism

# Inductance of a torus

Problem by zainul abidin

30 Nov 1999 00:00 WIB

Determine the self inductance of a torus with major radius *R* and minor radius *r, * which is tightly wound with *N* turns of wire. Assume that $R>>r$ and that the magnetic field within the region of the torus cross-sectional area, $A=\pi r^2$, is essentially of a long solenoid that has been bent into a large circle *R*.